From what they show, Super Kick Off is European, not Japanese. So, if the version we have is truly a Japanese version, then we're missing the European version, and they're missing proof of the Japanese version.

The only game listed here that they do not have proof for is Power Drive. And GameFaqs also lists this game, but does not provide any scans. I've seen this game in several lists, but no proof of its existence. So, for now, I'm going to take it off of my list until proof can be found.

[2nd Edit:]
Based on the list created by an avid ebay collector (see discussion below), I've made a few updates to this list.

"Hey, this is what I've seen cross ebay over the last several years. I think this might be correct, but I'm not certain." (paraphrased, of course)

With GameFaqs and Video Game Rebirth, at least people have posted box scans of the games. Sure, GameFaqs and VGR could be just as incomplete, but when they have something listed, at least they have some proof to back it up.

No, it's not like that. Iirc that username is a known GG collector. Scans do not back up a released games (see dozens 32X and SNES scans of unreleased games). Also, both sites are likely incomplete, they are for every system I researched.

edit:
and a simple google research shows he's indeed the collector he claims to be (see his introduction to the list.. heck, he even knows about Tec Toy in there)

I went through this guys list and matched up what he had to what I was already showing. The two lists were not far off. I've made some corrections where applicable to what's shown above. In addition to what I had listed above, it looks like where also missing this game gear release:

Also, although I understand the desire not to dump it yet, "Beggar Prince" should be listed as a game that has not been dumped yet.

Proof of Iraq War 2003 existing as a cart? There's a binary for it since ages (look in Goodgen 3.00), but AFAIK it's a basement-made project created with this http://www.sega-16.com/forum/showthread.php?t=4175, no place for it in No-Intro unless rules have changed again in the last year

Other than Beggar Prince, there's Legend of Wukong too, but the latter is too new, dumping and releasing it would be very bad manner...